Title: Almost Ricci-flat 4-manifolds
Abstract: A manifold is almost Ricci-flat if it
admits a sequence of Riemannian
metrics with diameter one, for which
the Ricci curvature goes to zero
uniformly. I will describe
results about the topology and geometry of
almost Ricci-flat 4-manifolds in the
noncollapsed case (joint work with
Vitali Kapovitch) and in the
collapsed case.